Resilience Scanner

Triple Bottom Line Analysis Tool for Green Infrastructure Assessment

Solution Overview

The Pittsburgh Water and Sewer Authority employed Impact Infrastructure's AUTOCASE tool to conduct triple bottom line analysis that incorporated environmental and social equity factors alongside financial considerations for green infrastructure projects.[1][2][4] This analytical approach enabled comprehensive evaluation of stormwater management alternatives across the combined sewer system in Pittsburgh, Pennsylvania.[3] The methodology supported decision-making for the City-Wide Green First Plan, which outlined innovative and cost-effective green infrastructure approaches to manage stormwater.[2]

Technical Components

The TBL-CBA framework, developed by Autocase, provided the analytical foundation for comparing infrastructure alternatives.[1] This framework was implemented using Autocase for Buildings and Autocase for Sites, a software tool that automated the TBL-CBA process.[1] The analysis considered a wide range of impacts across three categories: financial factors including capital costs, operations and maintenance costs, and property value uplift; social factors including air quality, greenhouse gas emissions, recreational value, and educational value; and environmental factors including water quality and flood risk.[1] The valuation approach was based on principles of welfare economics, measuring the value of impacts by the willingness to pay of affected individuals.[1] The analysis period spanned 50 years and applied a 3% discount rate, which represented the real discount rate recommended by the U.S. Office of Management and Budget for cost-benefit analysis of public investments.[1]

Implementation Details

Impact Infrastructure served as the platform partner for developing the value proposition for green infrastructure, working with the City of Pittsburgh and PWSA.[2] The analysis compared two infrastructure plans across three project areas: Washington Boulevard, Negley Run, and Four Mile Run.[1] PWSA analyzed the benefits of green infrastructure designs across 30 priority sewersheds throughout the combined sewer system.[3] The stormwater management practices outlined in the plan addressed U.S. Environmental Protection Agency combined sewer overflow mandates, improved the quality of local waterways, and addressed flooding issues.[2]

Benefits and Impacts

The analysis demonstrated that the Green First Plan represented the superior investment option. One assessment found the Green First Plan delivered a net benefit of $183 million over 50 years, which was $128 million more than the grey infrastructure plan.[1] Another evaluation showed the Green First Plan provided a net benefit of $133 million over 50 years, representing $199 million more than the grey infrastructure alternative.[1] The Green First Plan achieved a benefit-cost ratio of 2.0 compared to 1.3 for the grey plan in one analysis.[1] A separate assessment calculated the Green First Plan's benefit-cost ratio at 2.1 versus 0.7 for the grey plan.[1] The green-first approach created short-term and long-term jobs, improved air quality, and revitalized neighborhoods with green space and other amenities.[2]

Climate Adaptation Relevance

The green infrastructure approach directly addressed stormwater management challenges in Pittsburgh's combined sewer system, helping the city comply with federal mandates while improving local waterway quality.[2] The implementation reduced flood risk through nature-based solutions that managed precipitation more effectively than traditional grey infrastructure.[1]

Business Analysis

The triple bottom line cost-benefit analysis framework provided a comprehensive financial model that demonstrated superior returns for green infrastructure investments over a 50-year timeframe.[1] The methodology incorporated property value uplift alongside capital and operational costs, revealing economic advantages that traditional financial analysis might overlook.[1] The approach aligned with federal cost-benefit analysis standards by applying the U.S. Office of Management and Budget's recommended 3% real discount rate for public investments.[1] The analysis framework enabled public agencies to quantify social and environmental co-benefits, strengthening the business case for green infrastructure investments that delivered recreational value, educational opportunities, and air quality improvements.[1][2]

Sources